From: "Darrick J. Wong" Subject: [PATCH 3/7] mm: Provide stub page_mkwrite functionality to stabilize pages during writes Date: Mon, 09 May 2011 16:03:41 -0700 Message-ID: <20110509230341.19566.3876.stgit@elm3c44.beaverton.ibm.com> References: <20110509230318.19566.66202.stgit@elm3c44.beaverton.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: Jens Axboe , "Martin K. Petersen" , Jeff Layton , Dave Chinner , linux-kernel , Dave Hansen , Christoph Hellwig , linux-mm@kvack.org, Chris Mason , Joel Becker , linux-scsi , linux-fsdevel , linux-ext4@vger.kernel.org, Mingming Cao To: Theodore Tso , Jan Kara , Alexander Viro , OGAWA Hirofumi , "Darrick J. Wong" < Return-path: In-Reply-To: <20110509230318.19566.66202.stgit@elm3c44.beaverton.ibm.com> Sender: owner-linux-mm@kvack.org List-Id: linux-ext4.vger.kernel.org For filesystems that do not provide any page_mkwrite handler, provide a stub page_mkwrite function that locks the page and waits for pending writeback to complete. This is needed to stabilize pages during writes for a large variety of filesystem drivers (ext2, ext3, vfat, hfs...). Signed-off-by: Darrick J. Wong --- mm/filemap.c | 19 +++++++++++++++++++ 1 files changed, 19 insertions(+), 0 deletions(-) diff --git a/mm/filemap.c b/mm/filemap.c index fd0e7f2..1e096a0 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1713,8 +1713,27 @@ page_not_uptodate: } EXPORT_SYMBOL(filemap_fault); +static int empty_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) +{ + struct page *page = vmf->page; + struct inode *inode = vma->vm_file->f_path.dentry->d_inode; + loff_t size; + + lock_page(page); + size = i_size_read(inode); + if ((page->mapping != inode->i_mapping) || + (page_offset(page) > size)) { + /* page got truncated out from underneath us */ + unlock_page(page); + return VM_FAULT_NOPAGE; + } + wait_on_page_writeback(page); + return VM_FAULT_LOCKED; +} + const struct vm_operations_struct generic_file_vm_ops = { .fault = filemap_fault, + .page_mkwrite = empty_page_mkwrite, }; /* This is used for a general mmap of a disk file */ -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org